1. Field of the Invention
The present invention relates to a multilayer ceramic capacitor and a mounting board therefor.
2. Description of the Related Art
A multilayer ceramic capacitor, a multilayer chip electronic component, is a chip-shaped condenser mounted on the printed circuit boards of various electronic products such as display devices, liquid crystal displays (LCDs), plasma display panels (PDPs) and the like, for example, as well as computers, smartphones, mobile phones, and the like, to serve to charge and discharge electricity therein.
Since such a multilayer ceramic capacitor (MLCC) has advantages such as a small size, high capacitance, ease of mounting, or the like, such a multilayer ceramic capacitor may be used as a component in various electronic devices.
The multilayer ceramic capacitor may have a structure in which a plurality of dielectric layers and internal electrodes having different polarities are alternately stacked while being interposed between the dielectric layers.
In particular, in a power supply device for a central processing unit (CPU) such as a computer, or the like, voltage noise may be generated due to rapid changes in a level of a load current during a process of providing low level voltage.
Therefore, a multilayer capacitor has been widely used as a decoupling capacitor for suppressing voltage noise in such a power supply device.
Demands have been made for a decoupling multilayer ceramic capacitor to have low equivalent series inductance (ESL) in accordance with an increase in an operational frequency, and research into technologies for decreasing ESL have been, actively undertaken.
In addition, in order to supply power more stably, demands have been made for the decoupling multilayer ceramic capacitor to have controllable equivalent series resistance (ESR) characteristics.
In the case in which the multilayer ceramic capacitor has a ESR level lower than a desired ESR level, ESL of the multilayer ceramic capacitor and an impedance peak in a parallel resonance frequency generated due to plane capacitance of a microprocessor package may be increased, while impedance in a series resonance frequency of the multilayer ceramic capacitor may be extremely decreased.
Therefore, ESR characteristics of the decoupling multilayer ceramic capacitor may be easily controlled and improved, such that flat impedance characteristics in a power distribution network may be implemented by a user.
In connection with the controlling of ESR, using a material having high electrical resistance for an external electrode and an internal electrode may be considered. Using a material having high electrical resistance may be advantageous, in that high ESR characteristics are provided while a low ESL structure is maintained, as in the case of the related art.
However, in the case of using a material having a high degree of electrical resistance for an external electrode, a localized heat spot caused by a current channeling phenomenon due to a pin hole is generated. In addition, in the case of using a material having a high degree of electrical resistance for an internal electrode, an internal electrode material needs to be continuously changed so as to match a ceramic material according to high capacitance.
Therefore, since the method of controlling ESR according to the related art has disadvantages as described above, research into a multilayer ceramic capacitor allowing for control of ESR remains necessary.
In addition, with a rapid development of a mobile terminal such as a tablet PC, an ultrabook, or the like, in recent years, a micro processor has been converted to a high-integration product having a small size.
Therefore, since an area of a printed circuit board is decreased and a space for mounting a decoupling capacitor therein is limited, a multilayer ceramic capacitor capable of overcoming the disadvantages has been demanded.